Messages in this thread | | | Subject | Re: [PATCH] Reserve N process to root | From | Valdis.Kletnieks@vt ... | Date | Wed, 10 Oct 2007 15:50:14 -0400 |
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On Wed, 10 Oct 2007 09:46:22 EDT, Gustavo Chain said: > El Wed, 10 Oct 2007 15:14:06 +0930 > David Newall <david@davidnewall.com> escribió: > > That was what I thought you had in mind; it protects from some kind > > of fork bomb, right? But it doesn't seem useful unless you guarantee > > having a process already running (with CAP_SYS_ADMIN) *before* the > > bomb goes off. > > Not really, because fork bomb will never reach maximum pid possible. > And root will always have a "slot" to kill desired processes.
What David meant was that "root will always have a slot" doesn't *actually* help unless you *also* have a way to actually *spawn* such a process. In order to do the ps, kill, and so on that you need to recover, you need to already have either a root shell available, or a way to *get* a root shell that doesn't rely on a non-root process (so /bin/su doesn't help here).
Many distros will leave a /sbin/mingetty running on tty1 through tty6, and you *can* use those to get a root shell. David's point is that without something like that already in place, the patch doesn't help....
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